Web Paint-by-Number Forum
Topic #261: Slow opening
By Robert Shields (skweedle)

#1: Robert Shields (skweedle) on Dec 11, 2010

Recently, I am finding that opening new puzzles by clicking on "Home" is taking a very long time (sometimes 30 seconds). Since every other function moves quickly, is this due to the increasing number of puzzles being submitted or, is there something I can do to speed it up?
#2: Minnie Fuerstnau (m.fuerstnau) on Dec 26, 2010
Robert, I have struggled with this problem for years. I use an iMac G5, have installed more memory, and exhausted the ears and patience of any Apple user or tech I run into, and still have not solved it. For me it is a cumulative problem; the longer it is between when I totally shut down my computer, empty the caches, and generally "clean up" things, the worse the problem gets. (All of these actions have been suggestions from Apple techs.) None are very effective for long. I am resigned to it, but would welcome any new ideas, and wish you well in your quest for a better/faster puzzling experience. PBN is worth it!
#3: Teresa K (fasstar) on Dec 30, 2010
I also am frustrated with how long it takes to open "New Puzzles" and the Forum. It seems to take even longer after the recent browser updates.

Jan wrote that he uses a complex JavaScript code that gets loaded to our computers. So maybe that takes a long time to load each time, I'm not sure. Jan did remark in the FAQ that there are many issues of compatibility for JavaScript with many browsers. I have tried IE, Firefox, and Chrome. Chrome works the best for this site, but all of them are slow in loading certain pages here.
#4: Joe (infrapinklizzard) on Dec 30, 2010
It's probably on the server side. Every time you look at the Home page, the database custom makes a page for you that removes all the puzzles you've finished, that you've made, and that you've asked not to be shown there (like multiple solutions, etc). This means that the server-side software needs to look through an ever-increasing amount of data for an ever-increasing amount of users.

This is also true for the Forum page. The Find page should be a bit faster as it is a simpler join. Of all the pages, the Create and any of the puzzle pages should have the most javascript. So if those load quickly for you, then the problem is with an overloaded server, and there's nothing you can do on your end.

Note that the server also has to deal with checking of puzzles and the storage and sending-out of them. (Makers of puzzles may recognize the checker's timeout error of one second. That's an eternity in server time.) As more and more puzzles get made, and more and more people solve them, the lag will increase.
#5: bugaboo (bugaboo) on Jan 22, 2011
i agree with the last sentence posted
the lag seems to be getting a lot worse
#6: Jan Wolter (jan) on Jul 23, 2012
Joe's diagnosis is correct. The slowness is due to the overload of the server.

Obviously this is a fixable problem. Sites like Amazon.com remain fast with lots more users, but they have a little more money to work with.

The plan I have in mind is to eventually move the site to a more scalable server. The obvious candidates are Amazon's server farm or Google's server farm. This would mean dumping the mysql database that is the primary bottleneck now and changing over to some scalable distributed database. Most of these sites can dynamically ramp up when load is higher, adding more servers as needed, so the site never has to slow down so long as you have money to add more servers. Then I might set up a way for people to donate money to webpbn, where all the money would go to buying more server capacity beyond what I can afford.

However, doing this would require a complete rewrite of virtually all of the server code. I could keep the Javascript the same, but all the rest would have to go. And that's a pretty big task. Don't know when or if I'll get to it.

As it is, I think webpbn's growth has been capped by the speed problem. Which may or may not be a bad thing. Maybe this is the right size for webpbn. But it'd be nice if it was faster.
#7: Teresa K (fasstar) on Jul 23, 2012
I don't know about anyone else, but it doesn't bother me so much any more... I think I got used to the "slow serve." Also, I'm just happy to have free fun without being bombarded with advertisements (like hulu and skype and youtube).

Even without having to redo everything, Jan deserves some "real" appreciation. Anyone with a paypal account can send him a thank you "gift." Start here: http://www.unixpapa.com/white.cgi
#8: Jan Wolter (jan) on May 23, 2013
Joe implied in #4 that some of the slowness of the server might be due to the puzzle checker. Frankly, I didn't believe him.

But guess what? He was right. The checker is supposed to stop if it takes it more than a second of CPU time to check a puzzle. It wasn't. I'm not entirely sure what changed, since this used to work, but I think I've succeeded in fixing it. (If the checker just said "Checking..." forever instead of coming back with an answer or a "timeout" message, then you were seeing things failing.)

So yeah, this was chewing up CPU time on the webserver. Not a whole lot actually, since the checker runs at reduced CPU priority, meaning that if there is anything else that the CPU needed to do it would prefer that to running the checker. Still, having a lot of these processes running makes the system more sluggish in a variety of ways, and if too many accumulate it eats up the memory and could cause bigger problems.

So I think this is fixed now, but I'll keep an eye on things to make sure it is.

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